Specifically for Beltchecker:

Don’t change your profile picture when you get promoted. When you change your promotion history everyone that has voted for you gets a notification to reconfirm their vote. If you change your profile pic and it has yet to be verified no one can re-vote for you.

If you’re like me and get a lot of notifications, you will get lost in the shuffle before your profile picture gets verified. Then it will take much longer to get reverified. I suggest waiting until you’ve got the required number of votes before changing your picture.